The performance of a transseptal procedure is an essential part of a number of left-sided procedures for left-side therapy and/or device such as an ablation catheter, left atrial appendage occlusive device, percutaneous valve or clip, or some other left-sided cardiac procedure, such as valvuloplasty although currently used most frequently for percutaneous catheter ablation of atrial fibrillation. To successfully ablate and isolate the pulmonary veins (and other structures within the left atrium), a transseptal needle is typically advanced from the femoral vein into the right atrium and across the inter-atrial septum to place a long sheath into the left atrium. Such a sheath is necessary to position an ablation catheter in the left atrium and access left atrium tissue, including the pulmonary veins.
Many of these transseptal and ablation procedures are performed under administration of therapeutic warfarin, which subjects the patient to additional bleeding risks from the transseptal and/or ablation procedures. Even if anatomical landmarks are used with fluoroscopic guidance (i.e., catheter visualization) and intracardiac echocardiography, there are significant risks. Cardiac perforation with resultant life threatening cardiac tamponade (the filling of fluid into the sac around the heart which impedes blood flow out of the heart) has been reported in one percent of these patients.
Patients with paroxysmal atrial fibrillation may have fairly normal cardiac substrates with normal sized left atriums. The pressure that results from tenting of the foramena of the inter-atrial septum and the recoil of the needle (and lack of control as it penetrates cardiac tissue) has lead to the research and development of safer approaches for the transseptal and catheter ablation procedures.
In one approach a small needle within a J wire is used with the hope of blunting needle access in the left atrium. Even with this approach it is still possible to puncture the aorta or some other inadvertent tissue.
One problem with the standard transseptal approach is the mere fact that the needle travels from the safer right side of the heart to the more precarious left side of the heart. Structures that are at risk include: (1) the aorta, its root, and structures; (2) the left atrial wall; and (3) a coronary artery or vein.
A number of newer procedures may be performed by cardiac interventionalists who are much more comfortable with the retrograde aortic approach to the left heart than a standard right-sided septal approach. These doctors will want to place left atrial occlusive devices (such as the WATCHMAN® left atrial appendage closure technology from Boston Scientic Corporation) and perform left-sided valve procedures percutaneously (clips/valve repairs or replacements). A simple and safe retrogradw approach would allow these doctors to utilize their left-sided skills and thereby minimize complications rather than learn and perform the more risky and right-sided transseptal approach.